Prepare the compote by placing berries in a small saucepan over medium heat. Cook for 5-8 minutes with a lid on, stirring occasionally and smashing down with a spoon. Add a few teaspoons of sugar to sweeten if desired. I added 1 tsp. raw sugar (amount as original recipe is written). Transfer to a bowl to cool.
Using a tablespoon, drizzle cold water over the mixture and mix with a wooden spoon until it starts to form a dough. I added 2-3 Tbsp - you may need to add up to 5 Tbsp (as original recipe is written // adjust if altering batch size). It should be moist enough to form into a ball, but not too sticky to knead. Add more flour if it gets too wet.
Cut into 12 equal squares (not rectangles) and carefully transfer each to the baking sheet (amount as original recipe is written // adjust if altering batch size).
Place about 1 Tbsp of filling onto half of the squares (6 as original recipe is written), leaving a 1/4 inch border to seal the edges. Then use your finger to dot water around the edges so the two squares stick together. Top the squares with their matching halves and then seal lightly with a fork.
*Nutrition information is a rough estimate.